In U.S. Pat. No. 4,010,594 issued Mar. 8, 1977, a demand feed box filling and weighing system is described in which formed boxes are advanced on a continuously moving conveyor belt toward box ready positions at which their advancement is stopped until the ready box is advanced to the weighing and filling station opposite its ready position or advanced to another box ready position opposite a box filling and weighing station in accordance with the demand of the weighing stations. Heretofore, such boxes were formed by hand; that is, boxes were received in flat condition with score lines to facilitate proper folding of the box into a box form. When boxes were manually formed, the number of assembled boxes on the box feed conveyor means generally slightly exceeded the demand for such boxes at the filling and weighing stations. In attempts to supply additional filling and weighing stations, manual forming of the boxes and feeding of the boxes to the stations was often inadequate and the filling and weighing stations could not be run at full capacity.
Attempts to solve this situation resulted in the design of automatic box forming machines in which a two-piece box was discharged from the box forming machine in a partially assembled relation; that is, one box part was only partially ensleeved within the other box part so that before such a partially assembly two-piece box could be passed to a filling station, the two parts have to be pressed into proper telescopic relation by "stuffing" one box part into its full telescopic completed assembled relation with the other box part. Such two-piece boxes include a polygonal section tube of paper board having open ends and a second box part telescopically received within the first box part with a bottom formed thereon so that when the two pieces are fully telescopically related, the flaps on the outer tube can be folded over to provide a top box wall. The automatic box forming machine is capable of supplying more than enough partially assembled boxes to such a demand feed weighing and filling box system. However, since the box feed conveyor includes a continuously moving belt from the automatic box forming machine to the filling and weighing stations, the continuous pressure of boxes in back-to-back relation sometimes caused unwanted displacement of boxes from their preselected box ready position opposite a filling and weighing station. In addition to some displacement of a box in box ready position, the boxes are in back-to-back relation and because of the long line of boxes on the box feed conveyor, the frictional pressure between back-to-back boxes becomes too great for ready separation of a box from the line of boxes by transverse movement into a filling and weighing station.